The present invention relates to cermet compositions. It especially relates to cermet cutting tools for use in the cutting of metals and alloys.
As used herein, cermets shall mean sintered compositions containing a titanium carbonitride and a binder metal.
In the past, a variety of cermet cutting tools have been used to machine metals and alloys. These cermets have included those described in Rudy U.S. Pat. No. 3,971,656, which contain a carbonitride of titanium in solid solution with molybdenum or tungsten, and a binder metal or alloy, such as nickel and/or cobalt. Other cermet compositions containing titanium carbonitride are described in U.S. Pat. Nos.: 3,994,692; 3,741,733; 3,671,201; 4,120,719. Also of interest in this regard is H. Doi, "Advanced TiC and TiC-TiN Base Cermets," Science of Hard Materials (1986) pages 489-523. Commercial examples of such cermet cutting tool compositions (in weight percent, w/o) are shown in Table I.
TABLE I ______________________________________ COMMERCIAL CERMET CUTTING TOOL NOMINAL COMPOSITIONS Grade Element A B C D E ______________________________________ Ti 35.6 51.0 48 42.0 41.6 W 20.3 14.7 16.5 16.0 15.0 Mo 8.3 9.1 12.1 9.4 10.0 Ni 5.1 4.8 4.4 9.7 9.8 Co 8.2 4.9 4.9 1.9 1.7 Total 13.4 9.7 9.3 11.6 11.5 Ni + Co Ta 4.6 0.4 -- 8.8 8.5 Nb 1.2 0.4 -- -- -- V 2.9 1.4 -- -- -- C 9.7 9.9 -- 9.7 9.4 N 2.8 2.8 -- 3.1 3.4 O 0.5 -- -- -- -- ______________________________________
While the foregoing have performed well, there remains a need to produce a cermet composition cutting tool for turning applications having a toughness comparable to or better than prior art commercial cermet cutting tools, while having better wear resistance and significantly better performance (i.e., longer tool life) in metal cutting.